Gun equilibrator



Filed Sept. 12, 1952 3 Sheets-Sheet 1 INVENTOR.

LAWRENCE BRUEHL BY ATTORNEY July 26, 1960 BRUEHL sun EQUILIBRATOR 5Sheets-Sheet 2 Filed Sept. 12, 1952 LAWRENCE BRUEHL ATTORNEY 3Sheets-Sheet 3 Filed Sept. 12, 1952 m w 0 R N ms mm E m A L ATTORNEY GUNEQUILIBRATOR Lawrence Bruehl, Vestal, N.Y., assignor to InternationalBusiness Machines Corporation, New York, N.Y., a corporation of New YorkFiled Sept. 12, 1952, Ser. No. 309,345

7 Claims. (CI. 89-37) In modern weapon design it'has been the generalpractice to move the gun forward relative to the carriage and locate thetrunnions of the tipping parts closer to the breach of the gun andconsiderably in the rear of the center of mass of the gun parts. In gunsmounted on tanks, such mounting with the trunnions close to the breachis an advantage in that larger and longer shells can be handled moreeasily and also more room is available for crew and equipment. Thiscreates a condition of muzzle preponderance which must be equalized,otherwise there will be undue strain on the elevating mechanism anddiificulty in elevating the gun. Devices known as equilibrators havebeen used for this equalizing purpose. Such equilibrators exert a forceon the tipping parts which tends to elevate the piece, the torque beingsubstantially equal and opposite to that produced by the unbalancedweight of the gun forward of the trunnions. Equilibrators of the priorart have been of the counterbalance type, spring type, or of thepneumatic type.

In the use of guns in tanks, space limitations have hindered theapplication of equilibrators. Equilibrators of the counterbalance typeare extremely heavy and those of the spring type are also bulky.

According to the present invention a hydropneumatic equilibrator isprovided which is compact and designed to be mounted above the gunbetween the gun and turret. Equilibrating force is applied to the gun bythe compression of gas in the equilibrator system and, in addition,provision is made for applying a supplemental or augmentingequilibrating force when such supplemental force is needed. Guns used intanks usually are provided with an elevating system and in moderndesigns this elevating system is of .a hydraulic type. There is anelevation cylinder, and provision is made to force liquid from one sideof the piston to the other, thereby elevating or depressing the gun.

According to the present invention and as an object thereof, use is madeof the elevating cylinder to detect unbalanced forces which would impedeelevation of the gun. After detection of such unbalanced forces,provision is made to use these forces for'operating a valve, which valvein turn, through a hydraulic arrangement, applies supplementalcounterbalancing pressure to the equilibration system. This supplementalcounterbalancing pressure may be positive or negative, i.e. it may be apressure added to or one subtracted from the normal pressure created bythe compression of gas in the equilibration system.

Provision is made in the equilibration system by means of a diiferentialpiston arrangement for applying the augmenting pressure to theequilibration system when unbalanced forces are detected. The augmentingpressure could be directly applied to the equilibration system if asufficiently large equilibration cylinder and piston were used. But, inorder to conserve space, a small equilibration cylinder and piston ispreferable in which case a differential piston arrangement is necessaryto boost the pressure of the tanks main hydraulic system.

B-y the provision of the foregoing improved equilibration system, theequilibrator structure can be made quite compact, turrets may be keptrelatively low, and a lower silhouette may be obtained. Additionalspacewill also be available in the turret for ammunition storage andelevation of the gun can be effected with less physicaleifort.

In the design of equilibrators, provision is made to change thecounterbalancing pressurein accordance with the angle of elevation ofthe tipping parts of the gun. This is done by properly locating thepoint of attachment' of the equilibratorto a fixed structure such as atan-k turret and also locating the point of attachment of equilibratorto the gun and by properly coordinating these geometrical relations tothe counterbalance force exerted by the equilibrator throughout thevarious angles of elevation assumed by the gun. The weight of theunbalanced parts of the gun and their distribution about thecenter ofmass is-also a factor. However accurate the design may beastothelocation of attachment parts and taking into account the location of thecenter of mass of the unbalancedtipping parts of the gun, .the designedequilibrator frequently does not accurately compensate at certain anglesof tipping of the gun. Accordingly, there is frequently a residuum ofunbalanced forces at certain elevational angles and according to thepresent invention, such residual-forces may be compensated andcounterbalanced to thereby facilitate elevational adjustments 'of thegun.

One of the objects of the present invention is to provide an improvedequilibrator with means for supplying augmenting equilibrating forcewhen such force is needed.

The improved system of the present invention has;further utility in tankapplication because in tanks there is another angle which affectsequilibration. This is the angle of the tank itself with respect to thehorizontal. This angle varieswith undulations ofterrain andobviouslythe-designrelations of point of attachment of the equilibratorcannot take into accountsuch supplemental angular variations.Bydetecting unbalanced forces and utilizing these forces toapplyaugrnenting equilibrating pressure, the forces dueto supplementaltank angle may be compensated for and counterbalanced. Accordingly, gunelevation may be effected without undue effort both at variouselevational angles of the gun itself withrespect to a horizontal plane.

While the improved system ;is well adapted for tanks provided withmanual elevating means, the system is also advantageous for use inautomatically stabilized tank systems.

Further and other objects of the present invention will'be set forth inthe accompanying drawings in which;

Fig. 1 is a schematic elevation showing fragments of the turret and gunand showing the equilibration cylinder and piston as well as theelevation cylinder and piston;

\Fig. 2 is a longitudinal cross-section'of the equilibration cylinderand piston; I

Fig. 3 is a longitudinal cross-section of the differential piston andits control valve;

Fig. 4 is an end elevation of the differential piston device, takenalong the line 4-4 of'Fig. 3;

Fig. 5 is a fragmentary, transverse, longitudinal crosssection takenalong the line '5--5 of Fig. 4; and

.Fig. 6 is a schematic hydraulic diagram .of the entire equilibratorsystem.

A specific embodiment ofthis invention is illustrated in the drawings,in which 'Fig. 1 shows schematically a gun 11 which is pivoted about itstrunnions one of which is illustrated at 12, a fragment of a turret 13is shown and, pivotally connected to both the turret 13 and the gun 11,are two cylinder and piston arrangements. Together these constitutecertain elements of the equilibrator of this invention, one of thembeing the elevating means. The complete system of this equilibratorincludes a cylinder and piston device 16 which is pivotally attached tothe turret 13 and the gun 11 as illustrated. There is also an elevationcylinder and piston means 17, the primary purpose of which is toposition the gun in elevation. However, there is a further means commonto this elevation cylinder and piston which operates in conjunction withthe equilibration cylinder and piston device 16. This further means isnot shown in Fig. 1 but will be described below in connection with theother figures of the drawings.

The general purpose of the equilibrator, as has been explained above, isto apply a balancing force to the gun which is mounted in a muzzle-heavymanner. It will be evident that the force necessary to balance the gunwill vary with the elevation positions of the gun about its trunnionaxis. By using an equilibrator of the hydropneumatic type, such as thatof the present inven tion, a cylinder and piston may be arranged toapply a counterbalancing force to the gun about its trunnion aixs. Byarranging the location of the pivot points for the hydraulic cylinderand piston relative to the gun and turret, and by providing a properamount of pressure on the hydraulic fluid of this cylinder and piston,the counter-balancing force may be made to closely match the unbalancedforces of the gun in its various elevation positions. This matching offorces is never accomplished exactly throughout the range of elevationalpositions of the gun. At the positions of the gun where the forceapplied by the equilibration cylinder does not match the unbalancedforce of the gun about its trunnions, a correction may be made by meansof the system of this invention which makes changes in the hydraulicpressure of the equilibration cylinder.

Fig. 6 illustrates schematically the hydraulic system for anequilibrator of this invention. The equilibration cylinder and pistondevice 16 is composed of a cylinder 21, a piston 22, and a piston rod23. The cylinder 21 has a bracket 24 at the top, which bracket carries abearing 25 for pivotally fastening the cylinder by means of a pin 26.Pin 26 is carried by brackets 28 (shown in Fig. 1) which are integrallyfastened to the turret 13. Piston rod 23 has a similar bracket 29 whichcarries a bearing 30 for pivotally fastening the piston rod to the gun11 (Fig. 1) by means of a pair of brackets 31 fastened to the gun. Theposition of equilibration cylinder and piston device 16 may be reversedso that the cylinder bracket 24 is fastened to the brackets 31 on thegun, and the piston bracket 29 is fastened to the brackets 28 on theturret. This is a matter of choice. Hydraulic fluid is introduced into aspace 35 above the piston 22 by means of a passage 36 which runslongitudinally down the center of piston rod 23 and which is connectedto the hydraulic system by means of an ofi-set junction 37.

There is a separate hydraulic system for this equilibration cylinder andpiston device 16 which is composed of an accumulator 40 which has a gasfilled bladder 41 to act as the elastic means of this separate hydraulicsystem. The bladder 41 may be charged to an initial pressure of thehydraulic system by means of a valved gas port 39. This separatehydraulic system includes also a valve 42 for isolating the system fromthe main hydraulic system of the tank. The remaining elements of thisseparate system include fluid pipes 43, 44, 45 and 46 which connectaccumulator 40 to equilibration cylinder and piston device 16 and todifferential piston regulating device 48. The equilibration cylinder andpiston 16, together act to apply a counterbalancing force to the gun 11as pointed out above. It will be evident that this force varies as thegun is elevated or depressed since such elevation or depression willcause piston 22 to move up or down within cylinder 21. Such movement ofpiston 22 causes a variation in the hydraulic pressure of the separatehydraulic system because these movements of the piston displacehydraulic fluid in a positive or negative manner which fluid is thenforced into or out of accumulator 40 where the bladder 41 will becompressed or expanded. Compression of the bladder 41 increases thepressure in this hydraulic system, since the hydraulic fluid issubstantially incompressible and bladder 41 is acting as an elasticmember of the system in a well-known manner.

As was pointed out previously, the variations of counterbalancing forceapplied by the equilibration cylinder and piston 16 do not correspondexactly to the unbalanced forces set up by the gun in its variouspositions. To compensate for this failure to exactly counterbalance theunbalanced forces, differential regulating device 48 is used to regulatethe pressure in the closed hydraulic system of the equilibrationcylinder and piston 16. In device 48, there is a piston 49 which travelsin a cylinder 50. The position of piston 49 in its cylinder 50determines the amount of hydraulic fluid in space 51. Whenever theposition of piston 49 is shifted, the amount of fluid in space 51 willbe varied, and this in turn will vary the pressure in the closedhydraulic system of equilibration cylinder and piston 16 because space51 is connected by means of a passage 52 to fluid pipe 46 which, inturn, is connected to fluid pipes 44 and 43 and thence to accumulator40. Therefore, piston 49, if moved to the right as viewed in thedrawings, will force hydraulic fluid into accumulator 40 and therebyincrease the pressure. The change of volume of hydraulic fluid inaccumulator 40 is absorbed by bladder '41 which then applies greaterpressure to the hydraulic system since the gas within the bladder hasbeen further compressed. The positioning of piston 49 in order toregulate the pressure in the equilibration cylinder and piston system isaccomplished by means of a second piston 58 which travels in a cylinder59 and which is directly connected to piston 49 by means of a heavypiston rod 60. Piston 58 has a somewhat greater diameter than piston 49and may be positioned by means of introducing more or less hydraulicfluid into a space 61. The introduction of fluid into space 61 iscontrolled by means of a double-acting valve 64. This valve is connectedto the pressure supply and the return side of a general hydraulic systemwhich may be the main hydraulic system of the tank. The positioning ofdoubleacting valve 64- is accomplished by means of an unbalancedetecting device which, in this instance, may be composed of thecombination of hydraulic pipes 65 and 66 and the elevationcylinder-and-piston means 17. Pipes 65 and 66 lead from each side of apiston $4 in the elevation cylinder-and-piston means 17. There arethrottle valves 67 and 68 which act to reduce the effect of anytransient pressures due to shock conditions encountered in travelingover rough terrain. When the gun is unbalanced in such a way thatpressure in pipe 65 is increased (and pressure in pipe 66 is decreased),a valve core 71 of the double-acting valve 64 will be forced upward fromthe neutral position as illustrated in Fig. 6. This will open apassageway for fluid from a hydraulic pipe 72 through passageways to bedescribed in detail later, into space 61. Hydraulic fluid under systempressure will then flow into space 61 where it will act to force thelarger area piston 58 to move to the right carrying with it the smallerarea piston 49. Piston 49 in turn will force hydraulic fluid out ofspace 51 and into accumulator 40 where the gas in bladder 41 willconsequently be compressed and the hydraulic pressure of theequilibration system will be increased. This means that the forceapplied to the gun by the equilibration cylinder unit 16 will beincreased, until the gun is in balance again, at which time the pressurein pipe 65 will no longer exceed that in pipe 66 and valve core 71 willbe returned to its neutral position.

apropos Actually valve core 71 is not returned to its-neutral positionuntil pressure on the top exceeds that on the bottom of the valve corebecause there are no springs or other means of biasing the valve core 71to its neutral position. Therefore, there is a continual hunting actionwhich takes place but which is maintained at a non-harmful amplitude bythe natural damping forces and effects of the system. Considering thevalve core '71 as being effectively its neutral position, no more fluidmay flow into or out of space 61 of the differential piston unit 48.

it will be obvious that the reverse action takes place when an unbalanceof forces on the gun tends to pull the piston in the elevatingcylinder-and piston means down, because such action will increase thefluid pressure in hydraulic pipe so and decrease the pressure in pipe'65which will force valve core 71 down (as viewed in Fig. 6), and in thisinstance passageways will be connected from-space 61 to hydraulic pipe73. Hydraulic pipe '73 is connected to hydraulic common return pipes 74and 75, which, in turn, lead back to the sump and common return of themain hydraulic system which may be the casing of a hydraulic pump 77.Therefore, fluid will flow out of space 61 and pistons 58 and 19 willmove to the left as viewed in Fig. 6 which will reduce the pressure onthe equilibration hydraulic system in the reverse manner from thatdescribed above when an increase was assumed. That is, the movement ofpiston 4-9 to the left will increase the volume of space 51, which willallow fluid to flow into the added volume and the fluid so flowing willbe supplied by the accumulator 4% where the gas in bladder 41 is allowedto expand, reducing its pressure on the equilibration system.

When the equilibrator is first energized, the main hydraulic system willbe turned on so that the hydraulic pump 77, which is schematicallyillustrated, will produce system pressure in pressure pipes 73, 79, 8d,81, 82, 83 and 72. The equilibration hydraulic system may then becharged to main system pressure by opening a valve 85 located inpressure pipe 79, and valve 42 located in a connecting pipe asillustrated. This will charge the equilibrator system and accumulator 4bto system pressure. Then valve 85 will be closed and a hand-operatedbooster pump 86 will be operated to increase the pressure of theequilibration system until the gun 11 is balanced, i.e., until nodifference of force is necessary to operate a hand elevation pump 37 ineither direction (to elevate or depress the gun). After this, valve 42will be closed to isolate the equilibration hydraulic system and avoidany leakage back through the booster pump as.

The elevation cylinder and piston means 17 is operated by hand elevationpump $7 to determine the elevational position of the gun 11. A piston 94is secured to a piston rod 95 which is plvotally fastened to the gun 11by means of a conventional bracket illustrated. A cylinder 96 has abracket member 97 for pivotal connection to the turret 13. Bycirculating fluid from one side of the piston 94 to the other by meansof hand elevation pump 87, the piston 94 and cylinder 96 may berelatively displaced which will in this instance vary the position ofelevation of the gun 11. There is a conventional noback hydraulic valvedevice lilll located between hand pump 87 and the cylinder 96 in orderto prevent reverse circulation of fluid caused by road shocks or othercauses from being felt back in the hand pump 87. Pressure pipe 31 isconnected to hand pump 87 and acts to keep a bias pressure on theelevation cylinder and piston 17 to eliminate friction inside the casingof the pump 87. Without such a pressure pipe the handle of pump 87 couldonly be turned with great difficulty. Furthermore, pressure pipe 81provides a small pressure leak into the elevation system.

There is a bleed valve 103 inhydraulic pipe 104 which is connected toone end of space 51 in cylinder 50 of the diflerential piston regulatingdevice 48. The purpose of this bleed valve is to bleed off any trappedair in the equilibration hydraulic system when it is first put intooperation. There is also an indicator rod 105, which may be seen througha perforated guard sleeve 131. Rod 105 is connected into-piston 58andextendsthrough the left end of differential piston regulating device48 operating to give visual indication of the position of pistons 5-8and 49. Fluid is maintained in space '88 behind piston 22 oft-heequilibration cylinder 16 by means of hydraulic pipes :89-and 90 whichare connected to common return pipe 75. Likewise, there is ahydraulic-pipe 126 which is connected to-centra-l-space 127 which isbetween'the two-pistons SS and 49. The purpose of-these hydraulicconnections is to drain the spaces 88 and 1270f hydraulic fluidso thatthe pistons 58, 49 and 22 will not becomelockedin position by hydraulicfluid which may leak into these spaces.

Figs. 3, 4 and 5 show details of the differential piston regulatingdevice. A poppet valve 53, located at the right hand end of the'diiferential piston device as illustrated, is shown in its closedposition but will be open whenever there is a predetermined amount ofpressure on the mainsystem. This valve is pressure-operated and acts toisolate the differential piston regulating device from the equilibrationhydraulic system Whenever hydraulic pressure of the main system fallsbelow a given level. Hydraulic pipe 83 introduces hydraulic fluid underpressure from the main hydraulic system to a cylindrical space 1136.This fluid being under pressure tends'to-raise poppet valve 53 by meansof an integral piston 107. In opposition to this force, thereis a'springwhich tends to force the poppet valve downward onto its seat. Wheneverthe hydraulic pressure in the-main-system falls below a given level,spring 110 will close the poppet valve 53 and isolate the equilibrationsystem from regulating piston 51. The reason for having this provisionis to keep the equilibration cylinder and piston 16 (Fig. 6 operatingproperly (even though not being regulated for minor discrepancies) inthe event of hydraulic system failure of any sort. To illustrate thispoint, assume that main hydraulic pump 77 has failed, and an unbalancedcondition of the gun is detected by valve 64 which calls for addition offluid to chamber 61. Valve core 7-1 will therefore be moved so as toconnect pressure pipe 72 to the chamber -61. There being no pressure onthe fluid in pipe 72 because of the failure of pump 77, fluid would flowin-the reverse direction out of chamber 61 and this would only make theunbalance of thegun-worse instead of improving it. By having poppetvalve 53, however, the

failure of pump 77 would cause the-poppet valve to close by the actionof the spring 111 and then no actions of the differential piston device48 would eflect the equilibration cylinder and piston 16 in any Way. Thepoppet valve 53 is hydraulically balanced by means of an internalpassage 111 which introduces fluid from the equilibration hydraulicsystem into the space 112 above the poppet. When the poppet valve isopen, cha mber 51 of the differential piston regulator is directlyconnected to the equilibration hydraulic system by means of the passage52 and fluid pipe an. Upper cylindrical space 114, .in

which the piston 167 travels, is vented to the air by a passage 115 toallow free movement of the ,air above the piston 167 whenever it ismoved up or down inv the space 114.

The details of double-acting unbalance detector valvethe gun 11 aboutits trunnions 12. Such an unbalanced condition might be evidenced bynumerous devices which would actuate valve core 71, but I prefer to usethe means shown which utilizes the differential of pressure taken fromthe elevation cylinder by means of hydraulic pipes 65 (see Fig. 4) and66 as previously explained with reference to Fig. 6. The hydraulic pipes65 and 66 are connected to the spaces 121 and 122 at the ends of pistons117 and 116 respectively. Pipe 65 is not shown in Fig. 3 because of thelocation of the view taken.

Assuming a diiferential of pressure exists which will cause the valve 71to be moved upward, this will open the upper valve passage which isformed between piston 116 and a sleeve 123. Hydraulic fluid may thenflow from pressure pipe 72 into annular passage 119 and from there pastthe edge of piston 116 into a central annular section 124. From here,fluid may pass directly through passage 125 into space 61. The increaseof fluid in space 61 thus occasioned, tends to force piston 58 andconnected pis ton 51 to the right as viewed in Fig. 3 and hence toincrease the pressure in the equilibration hydraulic system as explainedabove.

The reverse action takes place at the regulating piston 49 if theunbalanced forces on the gun about its trunnion axis are in the oppositedirection. For example, assume that the gun 11 has come to rest in aposition where it is breach-heavy, i.e. the equilibration unit 16 isapplying more than enough force to balance the gun about its trunnions.In such case, elevation piston 94 (Fig. 6) is being pulled down in itscylinder 96 (Fig. 6), and so pressure in hydraulic pipe 66 is greaterthan that in pipe 65. This means that pressure in space 122 is greaterthan that in space 121, and so valve 71 will move downward. When valvecore 71 moves downward, upper piston 116 slides down in its sleeve 123,and so the upper valve connecting annular passage 119 with centralannular space 124 remains closed while lower valve, connecting annularpassage 120 with central space 124 around the edges of piston 117 and alower sleeve 129, is opened. The result is that chamber 61 is connectedto return pipe 73 via passage 125 and the lower valve path justdescribed as open, which connection withdraws fluid from chamber 61 andso acts to reduce the pressure on the equilibration hydraulic system ina manner described above.

The indicator rod 105 is clearly illustrated in Figs. and 3. Theindicator rod 105 is threaded into the face of piston 58 at the centerthereof and has a lock nut to securely fasten it in place as may be seenin Fig. 3. The rod 105 extends out the left end of the differentialpiston unit 48 and has an appropriate type of oil seal 128 to preventhydraulic fluid from leaking out around the rod. The free end of rod 105is encased in a perforated sleeve 131 which is threaded into the cap orhead end of cylinder 59 of the differential piston unit and secured by anut shown. The perforations in sleeve 131 allow the position ofindicator rod 105 to be visually observed. The purpose of this indicatoris to determine the position of pistons 58 and 49 in their cylinders sothat an initial position of operation which is at the center of travelof these pistons may be obtained when the equilibration system is firstset up.

There are adjustable stop members 132 and 133 located in the housing ofdouble-acting valve 71. These stops act to limit the travel of the valve71 in either direction by contacting the pistons 116 and 117 of thevalve. There are appropriate seals used wherever they are necessary tokeep the hydraulic fluid system tight. Also, within the system, thereare 0 rings or piston rings used, as illustrated, to obtain the desiredhydraulic action.

The details of the equilibration cylinder and piston 116 are clearlyshown in Fig. 2. It Will be seen that the pressure on the hydraulicfluid in chamber 35 at the end of piston 22 will determine the forceapplied at the bearings 25 and 30 which are rigidly attached to thecylinder 21 and the piston 22 respectively. This pressure is nothampered by any back pressure from space 88 because the fluid behind thepiston 22, i.e. in the space 88, is

under no pressure and is directly connected to the return side of themain hydraulic system by pipe 89.

Operation Referring to Figs. 1 and 6, a rsum of the operation of thesystem, covering the main features, is as follows: Whenever the gun 11(Fig. l) is not in balance about its trunnions 12, there will be anunequal pressure created on the two sides of the elevation piston 94within the elevation cylinder 17. This unbalance of fluid pressure willbe transmitted via the illustrated hydraulic pipes 65 and 66 (Fig. 6) tothe double acting valve 64 and will cause the core 71 of this valve tobe positioned in one direction or the other, so as to either admitadditional hydraulic fluid to the chamber 61 (behind large piston 58) orallow some fluid to be extracted from this chamber 61. This action willcause large piston 58 of the differential piston regulating device 48,to be moved in one direction or the other, and therefore to move at thesame time and to the same extent the small piston 49 of the sameregulating device 48. The movement of small piston 49 will eithercompress or expand the fluid located in chamber 51, at the end of thepiston 49. This compression or expansion of fluid in the chamber 51 isactually only a change of volume of this chamber, because it takes placein a separate independent hydraulic system that includes the passage 52and the hydraulic pipes 46, 44, 43 and accumulator 40, as well ashydraulic pipe 45 and the cylinder and piston device 16 to whichhydraulic pipe 45 leads. It is the gas in bladder 41 which is compressedor expanded. The change in pressure of the hydraulic fluid in thisindependent hydraulic system that is thus created, changes the forceupon the piston 22 within the cylinder and piston device 16 so that theequilibration force applied to the gun 11' by the cylinder and pistondevice 16 is also varied the corresponding amount. The variation inequilibration force that is thus created will be of such nature as totend to reduce the unbalance that was detected by the fluid pressures onelevation cylinder 17, to zero. Thus it will be evident that the actionof the system is such as to tend to maintain the gun 11 in completebalance about its trunnions 12 at all times.

While I have described a specific embodiment of the invention, manyequivalent variations will suggest themselves to one skilled in the art,and this disclosure is to be taken as illustrative and not in a limitingsense.

I claim:

1. An equilibrator of the hydropneumatic type for exerting balancingforces at various angles of elevation of a gun and including incombination, a source of system pressure, detecting means for detectingunbalanced forces which impede elevation of the gun, means controlled bysaid detecting means and utilizing system pressure for creatingaugmenting equilibration pressure, and means for applying saidaugmenting pressure to the hydropneumatic system of the equilibrator forthe purpose described.

2. An equilibrator of the hydropneumatic type for exerting balancingforces at various angles of elevation of a gun and including incombination, detecting means for detecting unbalanced forces whichimpede elevational adjustments of the gun, and means controlled by saiddetecting means for regulating the balancing forces of the equilibratorto compensate for any unbalanced forces detected.

3. An improved equilibrator for a gun comprising hydro-pneumatic meansfor exerting variable balancing forces at various angles of elevation ofthe gun, and including in combination unbalanced force detecting meansfor detecting unbalanced forces which would impede elevationaladjustments of the gun, a pressure regulating means for regulating theequilibrating pressures of the hydropneumatic means of the equilibrator,and means controlled by said detecting means for controlling the saidpressure regulating means.

4. An improved equilibrator for a gun comprising hydraulic cylindermeans for exerting variable balancing forces at various angles ofelevation of the gun, and including in combination unbalanced forcedetecting means for detecting unbalanced forces which would impedeelevational adjustments of the gun, differential piston hydraulic meansfor varying the pressure in said hydraulic cylinder means to regulatethe balancing force of the equilibrator, and means controlled by saiddetecting means for controlling said difierential piston hydraulicmeans.

5. An improved equilibrator for a gun comprising a hydraulic cylinderand piston coupling for exerting variable balancing forces at variousangles of elevation of the gun, and including in combinationhydraulically actuated unbalanced force detecting means for detectingunbalanced forces which would impede elevational adjustments of the gun,difierential piston hydraulic means connected to said hydraulic cylinderand piston coupling for varying the pressure in said cylinder toregulate the balancing force of the equilibrator, and hydraulic valvemeans controlled by said detecting means for controlling saiddifferential piston hydraulic means.

6. An equilibrator for guns adapted for tank use, said equilibratorhaving components operatively connected to the tank and to tilting partsof the gun, an elevating cylinder and piston structure also operativelyconnected to 1% the tank and to tilting parts of the gun, saidequilibrator having associated hydropneumatic means to provide variablecounterbalancing forces to the gun at variable angles of elevation ofthe gun, means to detect pressure dilferentials upon opposite sides ofthe piston in the elevating cylinder, diiferential piston hydaulic meansfor supplying regulating equilibration pressure to the hydropneurnaticmeans of the equilibrator, and means controlled by said detecting meansfor controlling the differential piston hydraulic means to efiectregulation of the equilibration pressure.

7. An equilibrator for guns adapted for tank use, said equilibratorcomprising a hydraulic cylinder and piston coupling operativelyconnected to the tank and to tilting parts of the gun, an elevatingcylinder and piston structure also operatively connected to the tank andto tilting parts of the gun, said equilibrator having a hydraulicpressure system connected to said cylinder and piston coupling forproviding variable counterbalancing forces to the gun at variable anglesof elevation of the gun, said pressure system including a differentialpiston for superimposing regulating equilibrium pressures into saidpressure system, means to detect pressure diiferentials upon oppositesides of the piston in the elevating cylinder, and hydraulic valve meanscontrolled by said detecting means for determining the position of saidditierential piston to cause the regulation of the pressure in said pressure system.

No references cited.

UNITED STATES PATENT oEEicE CERTIFICATE I REQllQN Patent Nos 2 946 263July 26 1960 Lawrence Bruehl It is hereby certified that error appearsin the-printed specification of the above numbered patent requiringcorrection and that the said Letters- Patent should read as correctedbelow.

Column 10, line 6, for "hydaulic" read hydraulic line 22, for"equilibrium" read equilibration Signed and sealed this 4th day of April1961a A tiE Q ERNEST W. SWIDER WXXXGE5 ARTHUR W. CROCKER AttestingOificer Acting Commissioner of Patents UNITED STATES PATENT erricrCERTIFEQATE i Q ECHQN Patent Noe 2 946 263 July 26 1960 Lawrence BruehiIt is hereby certified that error appears in the-printed specificationof the above numbered patent requiring correction and that the saidLetters- Patent should read as corrected below,

Column 10 line 6, for "hydaulic" read hydraulic line 22 for"equilibrium" read equilibration Signed and sealed this 4th day of April1961,

iii? ERNEST w. SWIDER WWW ARTHUR W. CROCKER Attesting ()fiiccr ActingCommissioner of Patents

